Oviposition behavior is not affected by ultraviolet light in a butterfly with sexually‐dimorphic expression of a UV‐sensitive opsin

Abstract Animal vision is important for mediating multiple complex behaviors. In Heliconius butterflies, vision guides fundamental behaviors such as oviposition, foraging, and mate choice. Color vision in Heliconius involves ultraviolet (UV), blue and long‐wavelength‐sensitive photoreceptors (opsins). Additionally, Heliconius possess a duplicated UV opsin, and its expression varies widely within the genus. In Heliconius erato, opsin expression is sexually dimorphic; only females express both UV‐sensitive opsins, enabling UV wavelength discrimination. However, the selective pressures responsible for sex‐specific differences in opsin expression and visual perception remain unresolved. Female Heliconius invest heavily in finding suitable hostplants for oviposition, a behavior heavily dependent on visual cues. Here, we tested the hypothesis that UV vision is important for oviposition in H. erato and Heliconius himera females by manipulating the availability of UV in behavioral experiments under natural conditions. Our results indicate that UV does not influence the number of oviposition attempts or eggs laid, and the hostplant, Passiflora punctata, does not reflect UV wavelengths. Models of H. erato female vision suggest only minimal stimulation of the UV opsins. Overall, these findings suggest that UV wavelengths do not directly affect the ability of Heliconius females to find suitable oviposition sites. Alternatively, UV discrimination could be used in the context of foraging or mate choice, but this remains to be tested.


| INTRODUC TI ON
Animal color vision mediates a multitude of complex behaviors. In general, color vision is achieved via wavelength discrimination (independent of intensity), where the inputs of two different photoreceptors (i.e., opsins, which differ in spectral sensitivity) are compared (Kelber, 1999;Kelber & Pfaff, 1999). In most insects, color vision is based on three photoreceptor classes, encoded by opsin genes, sensitive to ultraviolet (UV), blue (B), and long wavelengths (LW; Briscoe & Chittka, 2001;Kelber, 2006). The visual systems of butterflies are highly diverse with differing numbers of photoreceptor classes and sensitivities among families, genera, species, and even between sexes (Briscoe, 2008;McCulloch et al., 2017;Van Der Kooi et al., 2021). Visual system diversification in Lepidoptera has occurred through independent opsin duplications and is attributed to changes in light availability and habitat use (Sondhi et al., 2021).
Vision plays a crucial role in Heliconius behavior and guides fundamental processes such as foraging (Toure et al., 2020), interspecific and intraspecific communication (Estrada & Jiggins, 2008;Jiggins et al., 2001;Merrill et al., 2014) and hostplant selection (Gilbert, 1982). However, few studies have investigated the role of Heliconius visual systems from an ecological context (Dell'Aglio et al., 2018;Finkbeiner et al., 2017). Relative to other butterflies, Heliconius have some of the largest brains and invest heavily in the visual neuropile, suggesting selection for well-developed vision (Montgomery et al., 2016). In addition to the UV (UVRh1), blue (BRh), and long-wavelength (LWRh) sensitive opsins found in most insects, some species in the Heliconius genus possess a duplicated UV opsin (UVRh2; Briscoe et al., 2010). Additionally, some LWRh-expressing cells possess lateral filtering pigments that shift the spectral sensitivity toward red, enabling Heliconius to discriminate wavelengths in the long-wavelength range Zaccardi et al., 2006).
Across several species of the Heliconius genus, opsin expression is variable. Some species, such as Heliconius melpomene, have independently lost expression of one of the two UV opsins, with documented pseudogenization events (McCulloch et al., 2017).
Heliconius erato is sexually dimorphic-males only express UVRh2
whereas females express UVRh1 and UVRh2 ( Figure S1; McCulloch et al., 2016McCulloch et al., , 2017. It is possible that in H. erato, UVRh1 is located in the W-chromosome such as in H. charithonia (Chakraborty et al., 2022). A recent study investigated whether H. erato was capable of discriminating UV wavelengths: Finkbeiner and Briscoe (2021) tested H. erato females (which expresses UVRh1 and UVRh2), H. erato males (expresses only UVRh2) and H. melpomene (both sexes express only UVRh1) in a laboratory experiment and found that only H. erato females can discriminate between UV wavelengths. However, the ecological pressures that have driven these species-and sex-specific differences in visual perception remain unresolved.
While changes in opsin expression patterns within the Heliconius genus are well-documented (Catalán et al., 2019;McCulloch et al., 2016McCulloch et al., , 2017McCulloch et al., , 2022, the adaptive function of these changes in gene expression remains unclear. Understanding the selective pressures for UV discrimination in H. erato females may give us insight as to why expression of this gene greatly varies between and within Heliconius species. In contrast to males, female Heliconius spend most of their time searching for host plants for oviposition, which involves careful visual inspection (Benson, 1978;Brown Jr., 1981).
Females also avoid laying on hostplants where other eggs or larvae are present and Passiflora have evolved extra-floral nectaries that reassemble yellow eggs to discourage ovipositing females (Williams & Gilbert, 1981). H. erato females use leaf shape as an oviposition cue and can learn new shapes, driving the evolution of leaf shape plasticity in Passiflora (Dell'Aglio et al., 2016). The importance of choosing suitable Passiflora vines suggests that this behavior is under strong natural selection (Jiggins, 2017), and there is evidence that Heliconius female vision is fundamental for finding suitable oviposition sites. Therefore, UV wavelength discrimination in H. erato females may be an adaptation to facilitate hostplant recognition, but the role of UV vision in this regard has not been tested.  (Jiggins et al., 1996). These habitats may represent highly contrasting light environments; open forests receive direct sunlight, whereas dense shady forests are characterized by a "yellow-green" light spectrum due to reflection from the leaves (Endler, 1993). UV radiation also increases with altitude (Blumthaler et al., 1997). Prior work has suggested environmentspecific adaptations between these species: there is neuroanatomical divergence between H. erato cyrbia and H. himera, with the former showing higher investment in sensory regions of the brain important for visual processing, such as color vision (Montgomery & Merrill, 2017). This may be due to H. erato cyrbia living in a more complex and challenging visual environment.
Here, we test whether UV vision is used for oviposition in H. erato females and its closely related species Heliconius himera by manipulating UV wavelength availability. We address the following questions: (1) Does UV light affect oviposition behavior in H. erato cyrbia and H. himera? Given that UV is found under natural sunlight conditions, we expect that reducing UV availability will lead to a reduction in the number of eggs laid. (2) Does this behavior differ between species? Compared with H. himera, H. erato has a larger investment in the visual system (Montgomery & Merrill, 2017), we predict a stronger effect in this species. (3) How are UV cues in the hostplant perceived by females? Given that Heliconius females preferentially lay eggs on young nutritious shoots (Benson et al., 1975;Jiggins, 2017), we predict that UV reflectance will be highest for this part of the hostplant. Finally, we use visual modeling to quantify the stimulation of the H. erato visual system by its hostplant P. punctata.

| Butterfly rearing and maintenance
Wild Heliconius erato cyrbia were caught in forests near Balsas (3°51′26.0″S 79°34′05.3″W) and H. himera near Vilcabamba (4°15′57.3″S 79°13′41.4″W), in Southern Ecuador. Wild individuals were used to establish stocks at the Universidad Regional Amazónica Ikiam, Ecuador. The insectaries at IKIAM are in a clearing within a secondary forested area, reflecting the natural habitat of H. erato which are found at the forest edge (Jiggins et al., 1996). Butterfly stocks were kept in outdoor insectaries, in 2 × 2 × 2.3 m cages, fed a 20% sugar solution and had access to pollen from Lantana sp. and Psiguria sp. flowers. Eggs were collected from hostplants P. punctata (Jiggins et al., 1997), and the larvae were individually reared in pots on fresh leaves from P. punctata. For behavioral trials, we tested a total of 26 H. erato cyrbia and 10 H. himera females (less H. himera were tested due to low butterfly stocks).  (Greenwood et al., 2002;Hiermes et al., 2021;Honkavaara et al., 2008;Veen et al., 2017;Wright et al., 2017).

| Experimental design
The filters were attached to the top, left and outward-facing sides of the cage to filter the morning sunlight coming from the southeast ( Figure S2). We only fitted filters to these sides of the cages in order to prevent the cages from overheating. Because our experimental cages are in an outdoor insectary with plastic roofing made from polyethylene which blocks UV (Diaz & Fereres, 2007), there is effectively no source of UV light from the inside-and rightfacing sides of the cages ( Figure S4). We conducted the experiments in the morning, meaning that most of the incoming sunlight came from the east (downwelling, side welling left, and side welling out directions of the experimental cages). We took multiple irradiance measurements before, during and after the behavioral experiments to ensure that wavelengths in the UV range were being filtered out (see Figures S3 and S4). There was effectively no UV light from the inside-and right-facing sides of the cages ( Figure S4). The UVblocking filters successfully reduced the amount of UV wavelengths (300-400 nm) present in the experimental cages ( Figure S4). In contrast, UV wavelengths were present in the control UV+ treatment (i.e., with clear filters). The rest of the light spectrum-between 400 and 700 nm-remained unchanged between treatments ( Figure S3).
The experimental assay lasted 6 days, during which, a group of females (1-6 individuals) was introduced into each experimental cage. As the female butterflies were chosen randomly from the stock cages, some individuals (10 H. erato cyrbia and 1 H. himera) were tested twice (thus, these individuals were tested in 12 trials instead of 6). Individuals were introduced to the experimental cages 24 h prior to the experiment to acclimate and were confirmed to have laid eggs on a hostplant in the experimental cage overnight. On the first day of the experiment, the two cages were randomly assigned a light treatment (UV+ or UV−), thereby controlling for changes in natural sunlight during the assay by testing both treatments in parallel. The following days, each group was tested with the opposite treatment, alternating light treatments three times (UV+/UV−; Figure 1c).
Before each trial, the filters were fitted to the experimental cages and a P. puctata hostplant was placed at the center of the cage. For each trial, the butterflies were observed for 2 h between 8:30 and 12:00. During this time of the day, Heliconius are active, and females lay eggs (Jiggins, 2017). Based on the placement of the filters in the experimental cages ( Figure S2), we conducted the experiments in the morning when the majority of sunlight comes from the east.
Females could freely fly inside the cage, feed on artificial feeders and a pollen plant, and lay eggs. For each individual, we recorded the number of oviposition attempts, number of eggs laid, and the hostplant "part" (shoot, leaf, tendril, or stem) where the egg was laid ( Figure 1b). Oviposition attempts were scored as each time a butterfly landed on a hostplant and moved its abdomen with the ovipositor toward the plant, and each movement of the abdomen toward the plant was counted as an individual oviposition attempt. The sum of the three trials with the same treatment was combined for analysis.

| Reflectance spectrometry and visual modeling
Reflectance measurements of the hostplant P. punctata were taken using a Flame Miniature Spectrometer connected to a PX-2 xenon light source (spectral range 220-750 nm) and a UV/Vis reflection probe (Ocean Optics Inc.). All reflectance measurements were standardized with a white reflectance standard (Ocean Optics WS-1). For reflectance measurements, the illuminating and reflection probe was placed at a 45° angle at 1 mm from the plant tissue using a probe holder that was constructed in-house. We recorded three measurements per plant (shoot, stem, leaf; integration time: 2500 ms per scan). Irradiance and reflectance measurements were processed and visualized using the pavo 2.2.0 package (Maia et al., 2019). For each plant tissue, three biological replicates were measured across five individual plants (45 measurements per plant part).
The visual perception of the hostplant was modeled with previously published H. erato visual system data (McCulloch et al., 2016 using the pavo 2.2.0 package (Maia et al., 2019). For the visual model, we used the following photoreceptor sensitivities of H. erato females: UVRh1 λ max 355 nm, UVRh2 λ max 390 nm, BRh λ max 470 nm, LWRh-green λ max 555 nm, and a fifth photoreceptor class LWRh-red λ max 590 nm that occurs through expression of a red filtering pigment in combination with the green rhodopsin (McCulloch et al., 2016. We then calculated the photoreceptor quantum catch, which estimates the light captured by the visual system (Kelber et al., 2003) under each experimental light environment condition (UV+/UV−) against a green foliage background (Maia et al., 2013). The quantum catches were calculated as: where I(λ) is the irradiance measured in the experimental light conditions, S(λ) is the reflectance spectrum of the stimulus and R(λ) is the photoreceptor sensitivity based on the equations of (Govardovskii et al., 2000;Hart & Vorobyev, 2005).

| Statistical analysis
Statistical analyses were conducted in R (R Core Team, 2023), and plots were created with the ggplot2 package (Wickham, 2011;see Dryad repos itory for script in R Markdown). We fitted generalized linear-mixed models (GLMM) with the glmer function in the lme4 package (Bates et al., 2015) to test whether oviposition behavior was affected by the presence or absence of UV and tested how the number of oviposition attempts and/or eggs laid was influenced by the fixed effects (and their interactions): (i) treatment (UV+/UV−), (ii) weather (<50% cloud coverage/>50% cc./100% cc.) and (iii) species (erato/himera). Where GLMMs with Poisson distribution were overdispersed, we fitted negative binomial models with the glmer.nb function in the lme4 package. To avoid pseudoreplication (individuals were tested multiple times), individual id was included as a random factor. The random effect structure of the full models was selected based on Akaike comparisons, choosing the model with the lowest AIC value (ΔAIC >4; Burnham & Anderson, 2004;Sakamoto et al., 1986). Stepwise model reduction of the fixed effects based on statistical significance (Crawley, 2002) was then conducted using likelihood ratio tests (LRT) via the drop1 function to identify the minimum adequate statistical models. To estimate the parameters of significant fixed effects, we used parametric bootstrapping (nsim = 1000, pbkrtest package (Halekoh & Højsgaard, 2014)). For fixed effects with more than two categories (e.g., weather), we conducted pairwise comparisons using post hoc Tukey corrections with the emmeans package (Lenth et al., 2019).

| UV does not affect oviposition behavior
The availability of UV wavelengths did not significantly affect the

| Hostplant does not reflect UV and visual models show little-to-no stimulation of the UV photoreceptors
The spectral reflectance curves of different parts (shoot, stem, leaf, and white patches on the leaf) of the hostplant P. punctata are presented in Figure 5a. The observed reflectance curves are characterized by presence of light-absorbing chlorophyll (Chappelle et al., 1992); reflectance peaks are present at ~550 and >680 nm, and there is low reflectance below 500 nm, with very little reflectance in the UV range (300-400 nm).
To estimate visual perception of the hostplant by females in the UV-manipulated treatments, we calculated the photoreceptor quantum catches for the shoots of the hostplant-the part where most eggs were laid-against a green foliage background under each experimental condition (UV+/UV−; Figure 5b). Under natural sunlight (UV+), our models predicted minimal stimulation of UVRh2 and UVRh1 was not stimulated. In UV-absent conditions (UV−), neither UVRh1 nor UVRh2 were stimulated. In contrast, the blue photoreceptor (BRh) and the long-wavelength photoreceptors (LWRh-green and LWRh-red) were similarly stimulated under both lighting conditions. The long-wavelength receptor with red filtering pigments (LWRh-red) had the highest quantum catch, followed closely by the long-wavelength opsin (LWRh-green; Figure 4b).

| DISCUSS ION
Vision plays a crucial role in Heliconius behaviors, including mate choice (Estrada & Jiggins, 2008;Merrill et al., 2014), foraging (Toure et al., 2020), and hostplant selection (Gilbert, 1982). Through a gene duplication event at the base of the Heliconius genus, these butterflies gained a secondary UV-sensitive opsin (Briscoe et al., 2010;Bybee et al., 2012). However, levels of expression of this opsin varies both between and within species. For example, numerous species have independently lost expression of one of the two UV opsins, with documented pseudogenization events (McCulloch et al., 2017).
In H. erato, UV opsin expression is sexually dimorphic: females express both UV opsins, whereas males only express one (McCulloch et al., 2016).
In a recent laboratory study, male and female H. erato differed in UV wavelength discrimination (Finkbeiner & Briscoe, 2021).
However, the ecological pressures that have driven these sexspecific differences in visual perception remain unresolved. Given the differences in life history between male and female Heliconius butterflies, we predicted that UV wavelength discrimination might benefit female-specific behaviors such as oviposition. A strong body of evidence suggests the importance of visual cues for finding suitable hostplants for oviposition in Heliconius females (De Nardin & De Araújo, 2011;Dell'Aglio et al., 2016;Gilbert, 1982 Gilbert, 1981). However, our experiments suggest that UV wavelength discrimination in H. erato females is not an adaptation associated with oviposition behaviors. In addition to visual information Heliconius and other butterflies use other modalities during host choice, including chemosensation (Briscoe et al., 2013) and tactile information (Thiele et al., 2016). It is possible that at shorter distances, these other sensory modalities may play a primary role in hostplant decision.
In our experiments, the availability of UV light did not influence the number of oviposition attempts, nor the number of eggs laid by Heliconius females in the two studied species. While it is plausible that the lack of statistical power may have contributed to the nonsignificant findings regarding the effect of UV presence on the number of eggs, it is unlikely to be the sole explanation. Our spectral reflectance measures of the hostplant P. punctata provides a more likely explanation for these results. Overall, we found only minimal UV reflection in any of the hostplant parts of P. puctata where female butterflies laid eggs (Figure 4a). These results are consistent with the fact that UV reflectance is usually-but not always-low on leaves (Archetti et al., 2009), whereas, in contrast, many flowers reflect UV (Arnold et al., 2008). We also used female H. erato-specific opsin sensitivities (McCulloch et al., 2016 to estimate the photoreceptor quantum catches when viewing the shoots of P. punctatawhere most eggs were laid-in both light conditions (UV+ & UV−).
Neither UV photoreceptor (UVRh1 or UVRh2) was stimulated under the UV-absent conditions, and under natural sunlight (UV-present), only UVRh2 was minimally stimulated (Figure 4b). The absence of UV reflectance in the hostplant and little-to-no stimulation of the UV photoreceptors suggests that UV discrimination does not directly affect Heliconius female oviposition. However, it is important to note that these conclusions are based on estimates of visual system stimulation which are inherently limited (Dell'Aglio et al., 2018;Drewniak et al., 2020;Finkbeiner & Briscoe, 2021), further highlighting the importance of our behavioral studies.
The circuitry required for UV discrimination is metabolically costly and may have trade-offs with other components of color vision (McCulloch et al., 2016). Our experiments suggest that UV perception in H. erato females is not used during oviposition. An alternative is that H. erato females may use UV discrimination to detect previously laid eggs. Because of cannibalism in Heliconius larvae, females avoid ovipositing in the presence of conspecific eggs on the hostplants. However, neither H. erato eggs nor Passiflora egg-mimics F I G U R E 5 (a) Reflectance spectra of P. punctata, leafg represent green parts of the leaf while leafw represent the white spots on the leaves. Gray dotted lines indicate the normalized spectral sensitivities of H. erato. (b) Quantum catch estimates of the female H. erato visual system when viewing the shoots of P. punctata against a green foliage background. Quantum catches were calculated for each opsin UVRh1, UVRh2, BRh1, and LWRh including the red "receptor," which results from red filtering pigments shifting the sensitivity of LWRh pigment toward longer wavelengths Zaccardi et al., 2006). Gray bars show quantum catch estimates under UV+ environment and purple bars show quantum catch estimates under UV− environment. Error bars represent ±standard error. reflect wavelengths in the UV range (300-400 nm ;Finkbeiner & Briscoe, 2021) so this explanation seems unlikely.
Another possibility is that UV wavelength discrimination is used in female mate choice. In other butterfly groups, such as Colias and Eurema, UV reflectance is used by females for conspecific recognition and mate choice (Kemp, 2008;Silberglied & Taylor, 1973). In Heliconius, UV opsin duplication co-occurred with the evolution of a yellow pigment (3-hydroxyDL-kynurenine) that reflects UV (Briscoe et al., 2010;Bybee et al., 2012) and additionally in some species of Heliconius such as H. doris, the structural colored scales reflect UV (Wilts et al., 2017). However, there are populations of H. erato which do not show these yellow patterns, and it is currently unknown whether variation in UV vision exists between populations. Experiments have shown that both male and female H. erato individuals prefer to approach UV+ over UV− models (Finkbeiner et al., 2017); however, Heliconius females do not generally approach males to solicit mating, and these experiments cannot distinguish between UV-guided mating preference behaviors, or more general attraction to UV reflecting cues, which are common in flowers used by these butterflies (see below A more likely alternative function of UV discrimination in H. erato females could relate to foraging. Most insects that forage on flowers, such as bees and butterflies, can perceive UV (Briscoe & Chittka, 2001). Analysis of the reflectance of Psychotria and Psiguria-two pollen plants used by H. erato-found a UV component on the reflectance spectrum of their flowers (Finkbeiner & Briscoe, 2021). Due to egg production, female Heliconius have higher nutrient requirements than males, and may need to invest more in foraging for pollen resources. In particular, in H. charathonia, which also has sexually dimorphic vision (McCulloch et al., 2017), females have been shown to collect significantly more pollen than males (Mendoza-Cuenca & Macías-Ordóñez, 2005). Using a similar experimental design as the one used in the present study, future research could investigate the function of UV discrimination in the context of foraging.
An important caveat of our study is that we used individuals from populations collected from the wild on the western slopes of the Andes in southern Ecuador. Previous studies, which reveal evidence of sexually dimorphic expression of the UV-opsins, used H. erato petiverana individuals from Costa Rica (McCulloch et al., 2016(McCulloch et al., , 2017. The same subspecies, H. e. petiverana, and supplier was also used for laboratory-based UV wavelength discrimination experiments (Finkbeiner & Briscoe, 2021). The most recent common ancestor of the H. erato clade dates to 200,000-500,000 years ago and since then, over 15 H. erato populations with different wing patterns have evolved (Van Belleghem et al., 2017). Gene expression evolution can occur rapidly, especially in visual systems (Seehausen et al., 1997;Nandamuri et al., 2017). Therefore, H. erato populations might differ in their opsin expression patterns, though this has not yet been explored.
Experimental manipulation of ambient light using filters is a common method to simulate natural light environments or remove specific wavelengths altogether. Studies in a range of taxa, including aquatic (Hiermes et al., 2021;Wright et al., 2017) and terrestrial organisms (Greenwood et al., 2002;Honkavaara et al., 2008), have used this technique to investigate the evolution of animal visual systems and associated behaviors. However, to our knowledge, this is one of the very few studies (Veen et al., 2017) that used filters to modify natural sunlight conditions in a behavioral experiment. Using natural sunlight conditions as opposed to standardized artificial lighting is likely to better represent the lighting conditions found in these species habitats and may elicit more natural behavior. However, experiments under natural sunlight conditions are subject to considerable light intensity variation (see Figure S3). Thus, an unintentional difference in light intensity may affect the results. Indeed, weather conditions significantly affected oviposition attempts and the number of eggs laid in our study ( Figure S4). Butterflies made more attempts and laid more eggs on sunny days than on overcast weather. For this reason, the majority of behavioral studies that have manipulated the UV presence using UV-blocking filters have used standardized artificial lighting conditions (Greenwood et al., 2002;Hiermes et al., 2021;Honkavaara et al., 2008;Lewis et al., 2000). Nevertheless, under natural conditions-particularly in rainforests-light intensity varies rapidly (Endler, 1993), which will be better reflected by experiments manipulating wavelength under more natural conditions such as ours.
In our study, weather significantly affected oviposition attempts and the number of eggs laid. Compared with overcast weather, butterflies made more attempts and laid more eggs on sunny days ( Figure 4). This is in line with other studies of Heliconius butterflies where weather and light conditions have been documented to affect preference behaviors (Hausmann et al., 2021), and butterflies are more active on sunny days (Jiggins, 2017;Mérot et al., 2015).
Similarly, weather and light condition influence the behavior in other Lepidoptera taxa such as the activity in Noctulid moths (Yela & Holyoak, 1997), habitat use, and distribution in satyrine butterfies (Ide, 2002) and mating activity in the Precis coenia (Mcdonald & Nijhout, 2000). Overall, these findings highlight the broader significance of weather and light as key factors shaping the behavior of butterflies and moths across different taxa.
In conclusion, Heliconius color vision is fundamental for guiding behaviors, including mate choice, oviposition, and foraging. In contrast to H. erato males, H. erato females express two UV-sensitive opsins and can discriminate between UV wavelengths, but the selective pressures driving sexual dimorphism remain unresolved. By manipulating the light environment under naturalistic conditions, we show that UV perception in H. erato females is unlikely to be an adaption relating to oviposition behaviors. However, it is important to note that our findings are based on relatively few specimens due to limitations in our stocks. To strengthen the validity of our results, future experiments should consider expanding the sample size. Thus, the selective pressures driving sexual dimorphism remain unresolved. Further research is required to better understand the evolutionary processes that have sex-specific differences in visual perception in Heliconius. funding acquisition (lead); project administration (lead); resources (lead); supervision (equal); writing -review and editing (equal).

ACK N OWLED G M ENTS
We are very grateful to anonymous referees for manuscript feedback. We are grateful to the Universidad Reginal Amazónica Ikiam for support in Ecuador. We thank Lucie Queste and Sophie Smith for thoughtful discussions and for assistance in the insectaries. We also thank Anderson Yumbo and Mariana Silva who contributed to data collection.

This research was funded by a European Research Council (ERC)
Starter Grant (851040) to R.M.M.

CO N FLI C T O F I NTER E S T S TATEM ENT
The authors have no conflict of interest to declare.

O PEN R E S E A RCH BA D G E S
This article has earned an Open Data badge for making publicly available the digitally-shareable data necessary to reproduce the reported results. The data is available at https://doi.org/10.5061/ dryad.7m0cf xq0h.

DATA AVA I L A B I L I T Y S TAT E M E N T
The data supporting this study are available in the Dryad repository